WO1993010926A1 - Procede de regulation de l'oxydation et de la calcination de sables de fonderie uses - Google Patents

Procede de regulation de l'oxydation et de la calcination de sables de fonderie uses Download PDF

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Publication number
WO1993010926A1
WO1993010926A1 PCT/US1992/009441 US9209441W WO9310926A1 WO 1993010926 A1 WO1993010926 A1 WO 1993010926A1 US 9209441 W US9209441 W US 9209441W WO 9310926 A1 WO9310926 A1 WO 9310926A1
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WO
WIPO (PCT)
Prior art keywords
waste
firebox
sands
calcining chamber
sand
Prior art date
Application number
PCT/US1992/009441
Other languages
English (en)
Inventor
Robert S. L. Andrews
Gerald J. Reier
Original Assignee
Gmd Engineered Systems, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gmd Engineered Systems, Inc. filed Critical Gmd Engineered Systems, Inc.
Publication of WO1993010926A1 publication Critical patent/WO1993010926A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/142—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving along a vertical axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J6/00—Heat treatments such as Calcining; Fusing ; Pyrolysis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • B01J8/26—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with two or more fluidised beds, e.g. reactor and regeneration installations
    • B01J8/28—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with two or more fluidised beds, e.g. reactor and regeneration installations the one above the other
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • B01J8/36—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed through which there is an essentially horizontal flow of particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09C—RECLAMATION OF CONTAMINATED SOIL
    • B09C1/00—Reclamation of contaminated soil
    • B09C1/06—Reclamation of contaminated soil thermally
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
    • B22C5/08—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by sprinkling, cooling, or drying
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
    • F23G5/30—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having a fluidised bed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/20—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays
    • F23N5/203—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays using electronic means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2223/00—Signal processing; Details thereof
    • F23N2223/08—Microprocessor; Microcomputer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2225/00—Measuring
    • F23N2225/08—Measuring temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2233/00—Ventilators
    • F23N2233/06—Ventilators at the air intake
    • F23N2233/08—Ventilators at the air intake with variable speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2237/00—Controlling
    • F23N2237/16—Controlling secondary air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2237/00—Controlling
    • F23N2237/18—Controlling fluidized bed burners
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/18—Systems for controlling combustion using detectors sensitive to rate of flow of air or fuel
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S241/00—Solid material comminution or disintegration
    • Y10S241/10—Foundry sand treatment

Definitions

  • the present invention relates generally to a method for reclaiming used foundry sands and, specifically, to a method for controlling the oxidation of residual organic binders and calcination of residual inorganic binders adhering to the surface of sand grains in waste foundry sands.
  • Foundry sand is commonly used to make core molds into which ferrous and non-ferrous metals are cast.
  • the core molds consist of sand bonded with special additives including inorganic binders such as clay and organic binders, such as phenols, melamine, or urea formaldehyde.
  • Reclaiming Foundry Sand and assigned to the assignee of the present invention, presented a novel method for reclaiming mixtures of both organic resin-bonded sands and clay-bonded sands.
  • the method utilized a triple fluid bed thermal reactor which combined thermal and abrasive action within the beds to remove both resin-bonded and clay-bonded materials in one continuous operation.
  • the present invention is directed to further improvements in thermal sand reclamation techniques by providing precise control of the temperature and oxygen content in the fluidizing gases used in the previously described reactor fluid beds, particularly in the calcination fluid bed. It is this stage in the reclamation process that determines whether the inorganic binders are separated from or fused onto the used sand grain surfaces. While other thermal reclamation techniques have been utilized in the prior art in an attempt to reclaim waste foundry sand utilizing organic resin binders, those techniques employing fluid bed technology generally inject and burn any supplemental fuel gas required to heat the sand bed in and into the sand bed itself. Precise temperature control of such a random fuel mixture was difficult or impossible to achieve and extreme unevenness of heat within the bed resulted.
  • the present invention has as its object to provide a method for controlling the rate of oxidation and calcination of a random mixture of organic and inorganic bonded waste foundry sands to ensure consistent physical and chemical sand properties when reused with organic binders.
  • a further object of the invention is to maximize the desirable physical properties of the rebonded molds and cores, allowing the use of the same or less resin binder than with new sand, as a result of consistent sand qualities very similar and equal to the qualities of new sand.
  • the method of the invention is used for controlling the oxidation and calcination of waste foundry sands during a thermal reclamation process where the waste foundry sands have binders with a fuel content adhering thereto.
  • the waste sands are passed to a calcining chamber having a top, a floor and connecting sidewalls.
  • the floor of the calcining chamber is provided with a plurality of vents and the calcining chamber is connected to a separate firebox capable of producing fluidizing hot gases for fluidizing the waste sands within the calcining chamber and forming a fluidized sand bed.
  • the fluidizing hot gases are introduced to the calcining chamber by means of the floor vents.
  • Combustion means are provided in the firebox for producing the fluidizing hot gases.
  • the combustion means includes a burner, a source of supplementary fuel for the burner, a source of primary combustion air for the burner and a source of secondary combustion air for the firebox.
  • a first signal generating means is provided for producing a first signal representative of the temperature of the waste sands within the fluidized sand bed.
  • a second signal generating means produces a second signal representative of the volume of available free oxygen in the fluidizing hot gases within the firebox and in turn entering the calcining chamber through the floor vents.
  • Control means are provided for analyzing the first and second signals and for precisely controlling the temperature of the waste sands within the fluidized sand bed with respect to a preselected set point by adjusting the rate of waste sand feed entering the calcining chamber and by adjusting the quantity of supplementary fuel totally combusted in the firebox.
  • the control means is a proportional, integral, derivative control system under the command of a preprogrammed logic computer.
  • a heat energy requirement is calculated for calcining the waste foundry sands within the calcining chamber.
  • the heat energy requirement is calculated by combining the heat energy content of the binder fuels adhering to the waste sand grains entering the calcining chamber, together with the heat energy content of the combusted fluidized hot gases produced by the combustion means in the firebox.
  • the control means is operated to vary the mass flow rate of waste sand introduced into the calcining chamber, the volume of supplementary fuel supplied to the burner, the primary air supplied to the burner and the secondary air supplied to the firebox depending upon the calculated heat energy requirement of the process.
  • the waste sands being introduced into the calcining chamber include sand grains having both organic and inorganic binders adhering thereto.
  • the mass flow rate of the waste sands introduced into the calcining chamber, the volume of primary air and fuel supplied to the burner and the volume of secondary air supplied to the firebox are all controlled to precisely control the temperature of the waste sands in the fluidized bed of the calcining chamber to maintain the temperature of the sands below a critical temperature at which the organic binders would be fused to the waste sand grains.
  • Figure 1 is a diagram showing the calculated heat energy requirement for varying resin binder fuels and natural gas inputs
  • Figure 2 is a similar diagram showing the heat energy requirement calculation under varying fossil fuel and natural gas inputs
  • Figure 3 is a schematic, block diagram of a control system which may be utilized to maintain precise control of the temperature of the waste sand grains in a triple fluid bed thermal reactor;
  • Figure 4 is a schematic diagram of the fluid bed reactor showing the waste sand feed drive, the firebox combustion supply lines and the thermocouple sensing points which make up a part of the control system.
  • thermoreactor 17 comprises a first stage fluid bed which rapidly raises the ambient temperature of the feed material to a fluid bed temperature above 350°F.
  • the first stage fluid bed temperature is maintained by the hot fluidizing air that has been heated by waste heat energy from the reactors' flue gas as it passes through a heat recuperator 19 and which is supplied to the first stage fluid bed through the floor vent 64, as will be subsequently explained.
  • a thermocouple 77 in the fluid bed 17, along with thermocouple 78, 79, 80 and 81 continuously monitor process temperatures.
  • the oxygen in the hot fluidizing air is used to begin oxidation of the organic binders present on the sand grains in the feed material during an approximate one hour retention time in the first stage fluid bed.
  • the organic compounds present in the feed material are principally fossil fuels, such as powdered coal, coke, pitch or aromatic hydrocarbons such as phenols, coal, tar and synthetic resins. These chemical compounds begin to be destroyed at elevated temperature by the heavily oxidizing atmosphere which is created within the hot air fluid bed 17.
  • the inorganic compounds entering the calcining fluid bed have their temperature raised by heat energy from the fluid bed to begin their calcination phase during the one hour retention time within the calcining bed.
  • the hot fluidizing gases are supplied to the calcining fluid bed 25 from a firebox 27.
  • the mixing of the combustion products and excess air takes place at a controlled rate within the pressurized firebox 27.
  • the firebox 27 is shown directly below the calcining bed 25 in Figure 4, it can be situated in other locations in close proximity to the calcining bed.
  • a burner 28 is mounted in the sealed firebox 27 to provide combustion. Primary air is supplied to the burner 28 through a primary supply line 75 while secondary air is supplied through a secondary supply line 76.
  • the products of combustion in the firebox are vented through a plurality of vents 40 in the roof of the firebox 27 which is also the floor of the calcining chamber 25 in the embodiment illustrated.
  • these inorganic compounds consist mainly of bentonite clays, either Western or Southern, China clay or fire clay, depending upon the type of metal cast upon the sand molds. Each type of clay has a characteristics pH which determines the optimum calcining temperature for the calcining chamber 25.
  • the aggregate dust, clay fines and metallic dust are transported out of the fluid bed 25 through duct 29 to mix with the other off-gases passing out ducts 30, 32 of the other, two chambers before being passed through the reactors heat recuperator 19.
  • the calcined aggregate remaining in the second stage bed 25 passes over a weir 31 and through an external by-pass duct 33 by gravity feed to a third stage or pre-cooling bed 35.
  • Ambient fluidizing air is supplied from a conventional rotary blower (not shown) through the supply line 42 and through vents 44 to the pre-cooling bed 35.
  • the temperature of the material entering the bed 35 rapidly falls to about 500 to 700°F due to the influx of ambient fluidizing air during the one hour retention time in the bed 35.
  • the sand is discharged by gravity feed over a weir 36 and through a passage 37 to a post-cooling stage, e.g., a fluid bed sand cooler, prior to clay de-dusting.
  • the hot air, heated as a result of cooling the aggregate down from its calcining temperature to the 500 to 700"F range is transported out of the fluid bed 35 through the duct 30 to mix with the off-gases from the other two chambers before being passed through the reactors' heat recuperator 19.
  • the heat recuperator 19 has internal air passageways 60 which are exposed to the heat in the waste gases exiting each of the chamber ducts 29, 30, 32. Ambient air is supplied from a rotary blower (not shown) to the internal passageway 60. The air is heated in the internal passageway 60 and is routed through a conduit 62 to the vent 64 in the floor of - li ⁇
  • the gases exiting the recuperator 19 pass through duct 66 to a cyclonic particle separator 68 with the fine particles passing out the top duct 70 to a dust collector (baghouse) and the coarse particles to be separated pass out the bottom duct 72.
  • the aggregate discharged from the post-cooling unit at ambient temperature (85 to 100°F) is fed into a pneumatic attrition clay de-duster to remove the residual calcined clay particles from the cracks and crevices of the aggregate.
  • Clay de-dusters of this type will be familiar to those skilled in the art and are commercially available, for example, the NECO Attrition Scrubber available from National Engineering Company of Chicago, Illinois. It is this stage where the residual clays are removed and the organic residues scrubbed from the sand grains, the final step that control the Acid Demand Value (ADV) of the aggregate with respect to its rebonding properties using a core binder system based on an alkaline catalyst.
  • the de-dusted aggregates are conveyed from the de-duster to bulk storage silos for reuse in either the clay-bonded or resin-bonded molding lines or for core making operations.
  • the stored heat energy in the refractory lining of the firebox 27 is depleted to a point where the thermocouple sensor 79 in the calcining fluid bed will signal the preprogrammed logic controller to shutoff the waste sand feed 15 to the preheat fluid bed which, in turn, will shutoff the degraded waste sand feed 23 to the calcining chamber.
  • the supplementary fuel gas supply (from supply conduit 74) has a pre-set minimum heat input equal to the heat loss of the firebox refractory lining.
  • the secondary air volume supplied through line 76 at this point in the process is also set equal to the minimum required to maintain 10% free oxygen and fluidization in the calcining sand bed.
  • the only source of heat input to the calcining fluid bed is the "available heat value" of the oxidizing organic compounds in the calcining fluid bed at the instant the waste sand feed 23 is shutoff.
  • the continuous cycling between the waste sand volume feed 11 and the supplementary fuel gas supply 74 is accomplished by means of a motorized, variable speed drive on the waste sand feeder 73 and a motorized variable port valve (84, 86, 88 in Figure 4) on each of the fuel 74, primary air 75 and secondary air 76 supply lines, which are controlled in a manner which will be explained in greater detail below.
  • the fuel and primary air are maintained at stoichiometric ratio throughout their operating range.
  • the secondary air is maintained at up to 100% excess over primary air volume and above minimum fluidizing air volume.
  • the speed of the waste sand feeder is calibrated at 33.34 pounds a minute per ton of reactor capacity based on a nominal residual binder content of 0.6% by weight of the sand aggregate or an "available heat value" of 153,000 BTUs. When consumed in the calcining chamber of the fluid reactor, this represents 27% of the process heat energy required for the thermal sand reclamation at about 1500°F and at 100% thermal efficiency.
  • the balance of the process heat energy plus the thermal losses of the system is supplied by the supplementary fuel, either natural gas, LP gas or light fuel oil combusted in the firebox 27.
  • the heat energy relationship between resin fuel and natural gas is shown in Figure 1 and the heat energy relationship between clay-bonded fuel and natural gas is shown in Figure 2.
  • the data for both types of fuel shown in Figures 1 and 2 is based on practical field operation of a fluid reactors of the type shown in Figure 4 and is used to compile process temperature set points, temperature ramp up and down rates. The data is also used to monitor nonstandard thermocouples from all zones within the reactor, to linearize their outputs, detect failures and to switch to a backup system when required.
  • a temperature sequence program calculates and controls heat energy levels for each zone using a PID algorithm. PID controllers will be familiar to those skilled in the art and are described, for example, in
  • PID controllers utilize a control action in which the output is proportional to a linear combination of the input, the time integral of input and the time rate-of-change of the input.
  • PID proportional plus integral plus derivative control action
  • FIG. 3 there is depicted a high level schematic block diagram of a control system which may be utilized to maintain precise control of the temperatures of the waste sand grains in a fluid bed thermal reactor.
  • the fluid bed thermal reactor 1 is depicted in block diagram form.
  • Analog output signals representative of fuel flow, primary air flow, secondary air flow and various chamber temperatures are coupled to analog input system 102.
  • Analog input system 102 is preferably utilized to convert analog input signals from the various thermocouples and flow meters into digital control signals which may be more efficiently utilized by a digital controller.
  • controller 104 the outputs from analog input system 102 are coupled to controller 104.
  • Controller 104 may be implemented utilizing any suitable digital controller; however, a preferred embodiment of the present invention implements controller 104 utilizing a PID controller having a relationship between an input and an output such as that specified above. Controller 104 also preferably provides various operator input devices necessary for an operator to initiate or terminate the process described. The outputs of controller 104 are then coupled to programmable logic controller 100 which utilizes those outputs in conjunction with various "recipes" stored within recipe storage 106 to control the oxidation and calcination of the waste foundry sands. These "recipes" are the specified relationships between the amount of natural gas required for a known amount of residual fossil fuel or residual resin binder fuel within the foundry sands to be reclaimed, for a preset process temperature. Examples of these relationships are set forth within Figures l and 2.
  • Programmable logic controller 100 is then utilized, in a manner well known in the art, to control the operation of fuel valve 84, primary air valve 86, secondary air valve 88 and variable speed drive control 73, as necessary to maintain the desired temperature sequences and heat energy levels for optimal oxidation and calcination of the waste foundry sands.
  • fuel valve 84 primary air valve 86
  • secondary air valve 88 variable speed drive control 73
  • programmable logic controller 100 may also be coupled to alarm system 108 to generate audible and/or visual alarms in response to an inability of the control system to achieve and maintain desired temperatures.
  • the method for controlling the oxidation and calcination of waste foundry sands of the invention produces consistent physical and chemical sand properties of waste sands containing a random mixture of organic and inorganic binders.
  • the method also maximizes the physical properties of the rebonded molds and cores, allowing the same or less resin binder to be utilized while ensuring the consistency of the sand quality.
  • the structure and operation of the fluid reactor 1 are described in greater detail in previously cited United States Patent Nos. 4,549,698 and 4,978,076, the disclosure of which is incorporated herein by reference. While the invention has been shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit thereof.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Soil Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)

Abstract

L'invention décrit un procédé servant à réguler l'oxydation et la calcination de sables de fonderie usés pendant un processus de régénération thermique. Les sables usés sont transférés à une chambre de calcination possédant un plancher, des parois latérales de liaison et un sommet. Le plancher de la chambre de calcination est pourvu d'une pluralité d'orifices de ventilation. La chambre de calcination est également reliée à un foyer séparé produisant des gaz chauds de fluidification servant à fluidifier les sables usés à l'intérieur de ladite chambre de calcination et constituant un lit de sable fluidifié. Les gaz chauds de fluidification sont introduits dans la chambre de calcination par l'intermédiaire des orifices de ventilation du plancher. En régulant avec précision la température des sables usés à l'intérieur du lit fluidifié, on obtient un produit plus consistant tout en maintenant la température desdits sables usés au-dessous d'une température critique à laquelle les liants organiques se trouvant sur les grains de sable se fusionneraient aux grains de sable usés.
PCT/US1992/009441 1991-12-06 1992-11-12 Procede de regulation de l'oxydation et de la calcination de sables de fonderie uses WO1993010926A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US803,047 1991-12-06
US07/803,047 US5251684A (en) 1991-12-06 1991-12-06 Method for controlling the oxidation and calcination of waste foundry sands

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Publication Number Publication Date
WO1993010926A1 true WO1993010926A1 (fr) 1993-06-10

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Cited By (2)

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Publication number Priority date Publication date Assignee Title
EP0998999A1 (fr) * 1998-11-07 2000-05-10 Timothy George Henson Système de récupération de sable de fonderie
CN103350189A (zh) * 2013-07-05 2013-10-16 广西玉林玉柴工业化工有限公司 铸造废砂干燥、冷却的方法及设备

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US6000644A (en) * 1997-07-31 1999-12-14 General Kinematics Corporation Method and apparatus for reclaiming foundry sand
DE19943732A1 (de) * 1999-09-03 2001-03-15 Epcos Ag Verfahren zur Anordnung zur chemischen Oberflächenbehandlung von Schüttgut
WO2002081127A2 (fr) * 2001-04-05 2002-10-17 Clayton Thermal Processes Limited Traitement de recuperation de particules liees
GB2394684B (en) * 2001-04-05 2004-11-03 Clayton Thermal Processes Ltd Reclamation treatment of bonded particulates
BRPI0822563B1 (pt) * 2008-07-24 2020-09-15 Hatch Ltd Método e aparelho para controle de temperatura em um vaso reator
US9488372B2 (en) * 2013-03-15 2016-11-08 James L Nester Fluid bed regenerative thermal oxidizer and a method for its use
CN104096794A (zh) * 2013-04-08 2014-10-15 于彦奇 粘土砂热法再生机
US11982442B2 (en) * 2015-02-27 2024-05-14 Morgan State University System and method for biomass combustion
CN108176807A (zh) * 2018-02-24 2018-06-19 共享智能铸造产业创新中心有限公司 砂热法再生设备
JP2021046543A (ja) * 2019-09-11 2021-03-25 Ｊｆｅエンジニアリング株式会社 固形化燃料及び被焼却物の焼却方法

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